Vapor-phase formation of alkyl isocyanate-derived self-assembled monolayers on titanium dioxide
Titanium dioxide (TiO2) surfaces were modified at atmospheric pressure by exposure to the vapor of alkyl isocyanates having different alkyl chain lengths (CH3[CH2]nN=C=O, where n = 3, 4, 7, 11, 15, and 17). Dynamic water contact angle measurements, X-ray photoelectron spectroscopy, and atomic force...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 25(2009), 5 vom: 03. März, Seite 2875-80 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2009
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Water 059QF0KO0R titanium dioxide 15FIX9V2JP Titanium D1JT611TNE Oxygen mehr... |
| Zusammenfassung: | Titanium dioxide (TiO2) surfaces were modified at atmospheric pressure by exposure to the vapor of alkyl isocyanates having different alkyl chain lengths (CH3[CH2]nN=C=O, where n = 3, 4, 7, 11, 15, and 17). Dynamic water contact angle measurements, X-ray photoelectron spectroscopy, and atomic force microscopy confirmed that the vapor-phase treatment produced self-assembled monolayers (SAMs) of the isocyanate molecules on the TiO2 surface through a carbamate linkage without any marked changes in surface morphology. The thickness and hydrophobicity of the isocyanate-derived SAMs depend on both the alkyl chain length and process temperature. As a control, an oxidized silicon (SiO2/Si) surface was treated under the same conditions. Water contact angle hysteresis for the SAM-covered TiO2 surfaces is greater than that observed for SAM-covered SiO2/Si surfaces, suggesting that SAMs on TiO2 surfaces are disordered and/or insufficiently cover the surfaces. This leads to their water sensitivity. Desorption kinetics are also strongly affected by the alkyl chain length, and the SAMs of adsorbed molecules with n = 15 and 17 are relatively stable among these six isocyanate-derived SAMs |
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| Beschreibung: | Date Completed 01.07.2009 Date Revised 21.11.2013 published: Print Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/la803564c |